1937-38 Willys Cooling Tech West Coast Willys Club

Mike Brattland

Here are some thoughts on dealing with
cooling your motor in a 37-38 Willys......

Radiator-Usually a downflow radiator works best with a large
upper and lower tanks giving good coolant capacity....and the
tallest and widest radiator which will fit ahead of your engine
between the inner fender wells with as much exposed to air flow
through the hood louvers. The radiator needs an inside the
hood air dam such as the stock Willys hoods came with to help divert
the incoming air into the radiator not allowing the air to by pass
the radiator. The stock air dam might work but more than likely you
may need to build a custom air dam fashioned after the stock air dam
which will work with the radiator you are going with in your
particular car. This is very important. Examples below.....and here
is a Bill Jansen diagram of how the air dam works regarding air flow
through your hood louvers below........You might also like to review
Bill Jansen's 37-38 Willys Cooling Page as well for more background
and answers.

Willys Cooling Diagram-Bill Jansen

Electric Fans-Always best to use pulling electric fans if
there is room between the radiator and the engine. If not, then
pushing fans is the alternative. Largest possible electric fan or fans to push
air through is very important. If it is a pulling fan, a full or
partial shroud will only make the cooling effort even more
efficient.

Air Flow-Whenever air get through the louvers in the hood
after flowing through your radiator, it needs to exit the engine
compartment otherwise it is like a dam and no matter how good your
fan and entry is for incoming air, there will be no air flow for removal
of the heat from your raditor. Some of your options are to open up the inner fender wells
on both sides in the areas of the stock louvers....removing as much
sheet metal as you can but not compromising the integrity of the
inner fenderwells for supporting your steel sheet metal front end.
Another simple option is to reverse the opening of your hood's fresh
air scoop which would allow air inside the engine compart free
passage out of the compartment. See the hood scoop on the pickup to
the right below. Scoop is reversed and stays open all the time for
this reason.

Willys Hood Inside Air Dam-Came on all the Willys cars and
trucks from 37-42....The air dam was designed and installed to fit
down onto the top of the radiator which the stock radiators had side
air dams as well so that air flowing into the engine via the louvers
of the 37-38 hoods would be diverted inside into the radiator and
not around it. Very important for making your cooling system work is
to make use of the air dam concept in your cooling system design.

Front End Scoop-Numbers of Willys owners make custom under the
front sheet metal air scoops which catch fresh air and divert it up
and into the front of the radiator in the engine compartment. The
other option is to cut a slight opening in the lower sheet metal
below the old Hand Crank Hole in the shape of a "slit" but a little
larger as this Willys delivery owner did on the right below.

Small Grills embedded into the lower Front Sheet Metal-Some
very clever fellows in the UK embedded small grills (engine hood
side grills from an English Popular or Anglia) into the front sheet metal
on either side of the Hand Crank Hole to allow direct fresh air
entry into the engine compartment and to the radiator. Some others
did the same thing by installing actual louvers into the stock sheet
metal on the lower front section on both sides of the Hand Crank
Hole.

Removing some of the Hood Louvers-some guys have actually
removed some of the hood loovers leaving larger openings in the
stock hood which allows more air flow into the engine compartment as
in the pickup pictured below.

Auxillary Cooling-Ray Fields in LA cleverly used two long
finned alum coolers, 36 to 42 inches in length hung up on the
running board L Frames where they cannot be seen plumbing them into
the engine heater circuit allowing another means to circulate the
hot water and expose it to the cool air on the underside of the car.

I used Ray' Field's idea to install two small and shorter finned
alum coolers right under and in front of the front stock crossmember
which were plumbed into the engine heater circuit. The finned
coolers pictured below are the same ones mentioned in the above
suggest for inside the running boards, exept those are much longer
than the ones below.

For Pickups-Rear Radiator Option-There are numbers of Willys
pickups running rear radiators, including Bob Hudson's in
Bakersfield, my own and others. They use normal steel pipe
(Thickwall) between the engine and the rear radiator normally of the
same diameter as the engine outlets and radiator inlets so that
short rubber water hose connectors can be found in your local auto
parts store. The steel pipe should
have typical radiator drains installed in the low section on each
side underneath to make it easier to drain when engine or cooling
system maintenance is required. The rear radiator needs to be
installed such that the radiator opening is higher than your engine
to help when bleeding the system of air bubbles. the egine water
pump will handle this extended system just fine. No additional water
pump is required. Electric fans mounted to pull air through the
radiator is the way to go coupled with a full shroud to pull maximum
air through the radiator. It can be mounted behind the cab or even
better at the back of the bed where it can catch air flowing over
the cab and down through the tailgate area. Pictured below is the
custom Ron Davis Racing double pass alum radiator with full shroud
and two large electric pulling fans which I use in my willys pickup.
the bottom picture shows the pipe hung underneather in the chassis
with a drain welded into it for draining the syste. I have used this
system now for 12 years and it works well.